


Coming of age

by spleenessy



Category: Original Work
Genre: Birthday Sex, Consensual Underage Sex, Demon, First Time, I just had one idea and it turned out into a 8k fic, Lust, M/M, Magic, Original Character(s), Plot What Plot/Porn Without Plot, Porn with Feelings
Language: English
Status: Completed
Published: 2020-10-29
Updated: 2020-10-29
Packaged: 2021-03-08 23:54:18
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 8,538
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27255265
Author URL: https://archiveofourown.org/users/spleenessy/pseuds/spleenessy
Summary: It's Caïn's sixteeth birthday and Park has come to greet him.Caïn has found out that he was a demon two months prior, and Park is still the only one who can comfort him, but, like, in a Park way. (Read: probably not the best way.)Caïn doesn't mind, though.
Relationships: Park Spellman/Caïn Zaïtsevski
Comments: 4
Kudos: 6





	Coming of age

**Author's Note:**

> This is very self-indulgent and also my first attempt at writing actual porn in English soooo, who knows how it's going to turn out? Anyway, please enjoy reading as much as I enjoyed writing <3

Caïn smiled brightly, somehow, he knew that even this distinguishable feature of him would disappear to leave space for sly smiles one day. He didn’t want to think about it, yet he could not deny that he was afraid of what he was going to become. Park knew, of course. Park always guessed what was in his mind, and if Caïn had asked him, once, if it was because he was reading his mind all the time, blushing because Caïn wondered if, consequently, Park knew about all the things he could think of regarding him, Park had answered: “No I don’t, you’re just really easy to read,” he had said with a smile, before brushing Caïn’s cheek with his finger.

Caïn smiled and he thought that he liked smiling and that maybe, even if he were to become the most atrocious demon, he would still have a nice smile. To be honest, he had a rather bad image of demons. He only knew about them what his grandparents had been willing to tell him, or what Park would say when he was telling his stories that Caïn was always listening to with great attention. Caïn had always thought of demons as heartless, stupid, and mad creatures who couldn’t control their instincts and were only driven by their supernatural nature. He knew there were seven kinds of demons, for each one of the seven deadly sins: pride, gluttony, wrath, envy, greed, sloth, and lust. They were all awful in their own ways but when hearing about them, Caïn always thought that lust and envy were the worst. He didn’t know exactly why, they just felt like scary, powerful, and unpredictable creatures that could mess up your mind with only a few tricks. Caïn feared demons.

He didn’t fear his mother, though. But that was maybe because he never really thought of her as a demon. She was his mom before being a supernatural creature, and he had acknowledged her nature only when his grandparents started talking about her with harsh words that Caïn did not always understand. They called her manipulative, sinful, they told Caïn that his father had been fooled by her beauty, her fake promises and illusions of happiness, and Caïn had always wondered why there was so much hate in their words when they were talking about her being a demon.

When he was six, Caïn ended up asking his mother why she couldn’t just become an angel, so that his grandparents would stop insulting her, and that she could go back with his father and they would all live as a united and loving family together at last. She had smiled, a soft smile, full of regrets and also amusement, and Caïn didn’t know what was so funny in his proposition until she explained to him that she could not change her very own nature and that even if she could, she would not. Caïn had asked why, and she had answered that she loved to be herself. Caïn had decided that he wanted to love to be himself too.

He thought it would be easy, he thought he would become the most beautiful of angels, as his grandparents kept saying, complimenting him on his beauty, his grace, encouraging him in everything he was doing by saying “good, you’ll be a perfect angel, like us, like your father”, and Caïn thought that everything would be fine for him as long as he was himself.

But Caïn wasn’t an angel.

He had cried a lot the day it had happened, a few months prior, when his irises turned red, one morning just after breakfast. He was just brushing his teeth and looking at his reflection in the mirror, and suddenly, his pale blue eyes were no more. At first, he had been afraid, he thought he was sick, or worst, possessed, cursed, something along those lines. He had cried and called his father and his grandmother had shown up, opening her arms to welcome him and reassure him but had suddenly frozen when she had seen his eyes.

Caïn wasn’t stupid. He was fifteen, and rather mature for his age, let alone one of the smartest kid in the boarding school – he knew when to recognize disgust on someone’s face, and disgust he saw in his grandmother’s eyes. Disgust, and fear, and disappointment. He had cried even harder after she had left.

Surprisingly, Park had shown up even before his own parents. Caïn wasn’t in the mood to talk nor joke around, but Park didn’t really care about his mood anyway and had stuck around. And they had talked.

They had talked about a lot of things, including Caïn’s newly discovered nature, his family, Park’s last adventure in South America, the weather, and how the new maths teacher was pretty hot. In the end, Caïn had felt better, and when he had thanked Park for it, Park had just shrugged with a smile. That was so Park like. Shrugging and smiling, looking at him with cat eyes that Caïn didn’t know how to describe nor decrypt, his chin nonchalantly resting on his hand and his gaze staring right into Caïn’s soul – or so he felt it that way. Caïn knew that Park would say that he didn’t care about his well-being, yet he had taken the time to reassure him, to cheer him up when Caïn was all depressed and worried about what was going to happen next, because, after all, he was now the thing that his grandparents had warned him the most about: a demon.

“Demons are awesome, and you’re going to be a great one,” Park had said, a finger under Caïn’s chin to make him look up to his eyes. Caïn had not answered anything. Park had barely brushed his lips, Caïn had leaned in for a kiss. Park had given him.

Caïn smiled because he was thinking about that kiss, again, for maybe the hundredth, thousandth time since it had happened. He had thought about it in class when he wasn’t paying attention to his teacher and the boring lesson; he had thought about it in his bed, when he couldn’t find sleep and was trying to empty his mind – or when he didn’t want to sleep and used his memory to relax, often with a hand between his legs and Park’s name on his lips.

Caïn smiled and Park smiled back.

“What are you thinking of?” Park asked, in a way that made it sound like he didn’t actually care about the answer and was just asking to be polite, but not in a polite way either, more like a curiosity, an interest he knew he would lose the next minute but was still happy to enjoy for a few seconds.

Caïn answered: “I thought you always knew what I’m thinking of.”

“Not always. I also told you that I don’t read your mind.”

“Why?”

Caïn’s question was genuine and Park seemed bored.

“Cause it’s not fun. I want you to tell me what you think of, or I want to guess. Reading is too easy.”

Caïn’s smile grew wider, his eyes shining to the soft light of his table lamp, red irises like blood, and Caïn was almost used to it now. He was not taken aback every time he saw his reflection in the mirror anymore. Actually, he even grew into liking it, at least a little.

“Guess, then.”

Park’s eyes were yellow, split pupil as of a feline, a cat, a tiger, probably any animal dangerous enough to be feared by most people. But Caïn didn’t fear Park, never had, never would. Park frowned but kept smiling.

“Be careful with what you wish for, Caïn.”

Caïn bit his lip. He could see the way Park was looking at him, at that lip Caïn just bit and almost hurt because he wasn’t used to the little fangs that were slowly growing since he had become a demon; at his eyes glowing with amusement and envy; at the pale skin of his neck that Caïn had carelessly exposed by opening one or two extra buttons from his shirt when they had come back to his room.

Caïn could see the way Park was looking at him and he loved every single part of it.

And Park knew.

Their lips brushed, their eyes locked and Park’s fingers caressed Caïn’s jaw in a delicate gesture that sent a shiver down Caïn’s spine. He wanted to kiss Park so badly, yet he didn’t want to give in too fast, he wanted Park to concede him the kiss, but he also wanted to resist. Caïn wanted to be the one to lead, or at least try, because he didn’t know how Park was going to react anyway. Maybe Park was going to reject him, mock him, or slip away at the last second. He could shrug it off with a smile and a word and disappear and not come back before the next year and Caïn would not be able to do anything about it. It scared him.

Park knew that as well.

“You think too much,” Park said in a low voice, “relax. I’m not going anywhere.”

Caïn wondered if he had read his mind this time, then realized he didn’t care.

“Just kiss me,” he ordered.

Park smirked, then leaned in and did it.

Only two months had passed since their first kiss and yet Caïn felt completely different from the person he was back then. He used to be surprised by how soft Park’s lips could be and how gentle he kissed him; now Caïn was just eager to feel more (more of his lips, more of him). Caïn was still a bit reluctant to admit that he was really going to be a demon, but he did not feel as awkward as when it had just happened. Now he was more or less accepting the fact that it was happening, or at least that he could not do anything about it, no matter how hard he tried. So, when Park kissed him, with his soft, gentle lips, Caïn opened his mouth and deepened the kiss without any hesitation.

Caïn didn’t want it to be just a kiss. He didn’t want Park to leave him right after it. Caïn was not the lost and whimpering teenager he was two months prior, and he hoped that Park would see that, that he would consider him as the adult he was becoming, the man he wanted to be. Caïn caught Park’s neck with his hands and Park ended the kiss.

“You’re cute, kiddo.”

Park’s smile was offending. Caïn pouted, which made Park’s smile grow even wider.

“I’m not a kid,” he said, defiant.

“You’re sixteen today,” Park simply answered.

“Your point being?”

Park seemed pretty amused by Caïn’s defiance, but he didn’t comment further on it. Instead, Park took Caïn’s chin between his fingers and came closer to his face, until their nose touched.

“You’re just cute,” Park said, and he kissed him again.

If Caïn tried to lead the kiss this time, he failed. Park grabbed his hair and made him open his mouth wider for their tongue to meet and intertwine, Park pushing deeper into Caïn’s mouth, and Caïn heard himself moan before even realizing it.

God, it felt so _good_.

“What was that?” Park asked when they broke apart again.

“Hm?” Caïn purred, his eyes fixed on Park’s lips, his body tensed and his fingers grabbed the fabric of Park’s shirt a little tighter.

“Did you just moan?”

Park kept smiling, Caïn ignored him.

“Yes, I did,” he answered without thinking about it.

“Cute,” Park said again, and Caïn rolled his eyes.

“I’m going to make you moan too and it’s not going to be cute,” Caïn said in a sharp voice.

Park laughed; a laugh too genuine to be innocent.

“Can’t wait to see that,” he said against Caïn’s lips, before kissing him again.

Park’s body was like a painting: he had tattoos everywhere, from the palm of his long hands, that were holding Caïn’s waist firmly as he laid him down on the bed, to his knees and the pit of his stomach that Caïn discovered when Park undressed in a few movements before climbing on top of him. Caïn did not even blush, he was just fascinated. He didn’t ask for permission before tracing with his finger the curve of one of some rune he had no idea of the meaning on Park’s skin. Park let him, smiling a little when he understood why Caïn was so impressed. After a moment, Park took his hand and drove it to his sides, intertwining their fingers while he slid it down his chest, slowly.

“You’re beautiful,” Caïn let out in a breath.

Park laughed.

“I know.”

Caïn wondered if every single tattoo had a meaning, or was an actual spell, or if Park just liked to get tattoos for fun. He didn’t ask because he knew that Park would most likely answer with a lie just to impress or make fun of him, and Caïn didn’t want him to ruin the mood already. So Caïn only stared with curiosity and fascination, his fingers following the black traces that were covering Park’s body in an almost methodical way.

“You like what you see?” Park asked, his voice lower, almost husky, which made Caïn look up to see his eyes again.

“I do,” he answered, “very much.”

Park’s smile was bright, Caïn lost himself in his eyes for a few seconds, which gave Park the time to come closer and kiss him again.

Caïn felt Park’s hands on his chest, then under his t-shirt and he heard him groan. He was going to ask what was wrong, but Park clicked his fingers and Caïn found himself completely naked immediately.

“Hey!” he exclaimed, surprised and a little taken aback by the cold air suddenly surrounding him.

“Oh, sorry, your clothes were bothering me.”

Caïn pouted because Park didn’t look sorry at all. He kept smiling and his fingers were tracing figures on Caïn’s chest.

“That’s not really romantic,” Caïn commented, “I thought you were going to undress me slowly and sensually.”

Park laughed again, and Caïn realized that he liked to hear him laugh, he felt a sort of pride in the idea of being the one to make the great sorcerer Park laugh so easily. Park kissed his temple, then his cheek, and his face stayed close to Caïn’s.

“Sorry, kiddo,” Park apologized, his hot breath on Caïn’s lips, “I’m not really the romantic type.”

The way he said it made Caïn shiver and he bit his lower lip. Instinctively, he had closed his legs to hide what he could of his nudity, but Park’s hand was now sliding down his chest and caressing his sides, lower, and lower, until he reached his thigh. Park’s touch felt ethereal, warm, and soft and Caïn felt immediately relaxed under it, his legs opened without him thinking about it.

Caïn kept looking at Park’s face, trying to memorize every single one of his features as their faces were close like they never had before. Caïn wanted to kiss Park so badly, everywhere, wanted to take the smile off his face, wanted his eyes to focus on him tonight and forever after that, wanted him, and only him, and when Caïn realized that, he finally blushed. Only then, he became aware of his own arousal and he felt so vulnerable, naked under Park, he almost wanted to ask him to stop.

Park seemed to realize it. He kissed him, a short kiss, nothing passionate in it, just a smack on his lips. Then he asked:

“You want me to stop?”

The hand caressing Caïn’s thigh had stopped.

“I’ll stop if you want.”

Caïn opened his mouth. Did he just panic because he had not exactly realized before now that he was going to have sex with Park? Yes. Was he taken aback by the sudden realization of his deep desire for Park? Also, yes.

So, did he want Park to stop?

God, _no_.

“Don’t,” Caïn eventually let out in a breath, “please-”

Fortunately, Park did not let him lose his words into some complicated and messy explanation about how he felt. Park just needed him to say that he wanted him to continue, nothing more. He did not hesitate much longer and Caïn finally felt his hand sliding down his crotch, making him gasp in surprise.

Park kissed his temple again, then his ear, and his voice was like a husky purr that made Caïn’s stomach drop.

“Don’t beg me, I might actually like it.”

Caïn opened his mouth to answer something, but nothing came but an incoherent babbling, and Park laughed before kissing him and shutting him up immediately. Caïn grabbed Park’s hair, the kiss deepened and Caïn felt like he was drowning in it. Park was everywhere: his tongue in his mouth, a hand between his legs, the other one on his chest, both caressing him with a tenderness that contrasted so much with the intensity of the kiss that Caïn didn’t know what he was supposed to believe anymore. Was Park gentle with him? Or provoking? What did he want from him in return? And how did he want it? Caïn had dreamed of this, many times, of Park on top of him, his hands on his body and his lips on his, yet he felt so unsure about what he was actually supposed to do now that it was really happening, he felt stupid. In his fantasy, Park was doing everything; everything he wanted, and everything Caïn asked him to do, and Caïn had nothing to worry about. Whereas right now, he was too worried, and it was beginning to annoy him.

“You think too much, kiddo,” Park said when the kiss ended. His lips brushed Caïn’s cheek. “Just let it go, I’m going to take care of you.”

Caïn relaxed a little, as if Park’s words were exactly what he needed to hear. Park always had that effect on him: he knew how to make him feel comfortable and calm, and Caïn trusted him (even though he knew he shouldn’t, because Park was Park, and as one of the most powerful sorcerers currently walking on Earth, he was to be handled with great precaution.) But Caïn was young and reckless and the only things he cared about right now were himself, and how Park was going to please him.

With his hand between his legs, sure, but what else? Caïn felt his arousal grow bigger at each movement of Park’s fingers around his cock and it was good, but it wasn’t enough. Caïn bit his lower lip again and realized that it hurt: his canines had grown bigger, sharper, and he slightly cut himself with it. He mumbled, frustrated, and awkward, he felt ridiculous.

“I want more,” Caïn whined without looking at Park, because he didn’t want to see him smile, but he heard his mocking laugh anyway.

“You’re so impatient,” Park whispered against his ear, his hand immediately left Caïn’s crotch and Caïn wondered if Park was going to stop everything, stand up, get dress, and leave him there because Caïn had pushed him and Park didn’t like that and so he was going to punish him for that.

As much as the perspective of a punishment sounded alluring to Caïn, he also thought that he was going to die of shame and frustration if Park stopped their intercourse right there. Caïn grabbed Park’s shoulder and forced him to stay close to him, too afraid to see him go, he crushed their lips together and kissed him hard, his teeth scraping Park’s lips in the process, and Caïn tasted iron on his tongue.

When they parted, Caïn licked his lips, his eyes locked on Park’s gaze. Park was panting, and Caïn loved it.

“Easy, Caïn,” Park’s tone had fallen from an octave, he put his hand on Caïn’s waist to force him to stay still since Caïn was desperately trying to press his body against his.

“Hm-hm”, Caïn answered, he reached for Park’s lips again, but Park stopped him with a finger and Caïn pouted.

“How do you want it?”

Caïn was surprised by the question, he didn’t understand it immediately.

“What do you mean?”

“Do you want me to top or to bottom?”

Caïn arched a brow.

“To bottom?”

Park sighed.

“Oh, I forgot you were just having your gay awakening with me.”

He didn’t seem annoyed, more like amused, and Caïn wondered what he meant by _gay awakening_ but guessed it had something to do with the fact that he had been touching himself thinking about Park for the last six months or so. Caïn wasn’t even surprised that Park knew about that.

“I meant: do you want my dick inside you, or do you want yours inside me?”

“Oh,” Caïn said.

He understood now. He just lacked vocabulary.

Caïn couldn’t help the smile when he answered, because he was happy Park took the time to ask him what he preferred, even if Caïn thought it was clear with the way he was acting toward him.

“I want your dick inside me, pretty please.”

Park smiled.

“Of course, you do,” he said, “you’re so needy.”

Caïn was about to complain, but Park kissed him, and Caïn immediately forgot about what he wanted to say. It wasn’t important – nothing was important when Park’s tongue was in his mouth, blowing his mind, and Caïn tightened his grip on his shoulders. Caïn felt Park’s hand down his crotch again but this time Park slid his fingers behind his cock and made Caïn spread his legs wider so that he could grab his butt. Caïn gasped and arched his back, surprised even though Park had been gentle.

“Relax, baby boy, I’m not going to do anything you don’t want.”

Park’s voice was like a purring against Caïn’s ears, soft and comforting, something he could not say no to, something he trusted and wanted to hear again, and again, like a loving melody. Caïn didn’t even notice the new pet name, it sounded so right he felt like Park had always called him that way – he loved it.

“I guess you don’t have any lub here,” Park said suddenly.

Caïn frowned again.

“Lub?”

“Lubricant- God, do I really have to teach you everything?” Park complained.

“Sorry,” Caïn said, annoyed, “You don’t often get to experience gay sex in a Russian catholic private school.”

Park laughed, amused, and Caïn smiled back.

“You would be surprised…” Park said with a sly smile, but he didn’t let Caïn react to it, “anyway, you’re lucky I’m the greatest sorcerer alive.”

Caïn giggled.

“Of course, you are.”

It had not taken a long time for Caïn to understand how much Park liked to be praised and Caïn had realized he kind of enjoyed the expression on Park’s face every time he would compliment him, so Caïn did not stop.

Caïn lost his smile the next second, though, because Park’s fingers were caressing him, and they felt cold and slimy and it wasn’t the most pleasant sensation. Park must have seen his discomfort as he kissed him slowly on the lips, taking his mind off what was going on between his legs. Caïn didn’t think it would be so easy, but it worked, and he relaxed in Park’s embrace, just enough for Park to slide a first finger inside him. Caïn squirmed immediately.

“Shh, just relax baby boy,” Park said before leaving kisses all over Caïn’s face, and Caïn tried to, it felt weird and uncomfortable – but it didn’t hurt.

Eventually, he felt more accustomed to the sensation, and he even started to enjoy it as Park kept kissing his cheeks. Caïn even dared to complain.

“Come on, I’m not a kid anymore, you can go faster than that,” he said and bucked up his hips at the same time to show Park that he wasn’t afraid of feeling more.

Park’s smile only widened.

“Only kids are this impatient,” he answered.

Caïn was truly offended, which only made Park laugh. Caïn avoided the kisses Park tried to give him after that and Park apparently decided to kiss his neck instead. Caïn could still feel his smile against his skin, his teeth brushing against his throat, it made Caïn shiver in expectation. And then Park added a second finger and Caïn hid his face in Park’s shoulder to avoid moaning.

“You’re doing great, baby,” Park purred against Caïn’s ear, and Caïn didn’t know what was hotter between Park’s voice or his cheeks but he was pretty sure his stomach had just dropped because of the way Park talked to him.

Park prepared him slowly and carefully, and if it felt weird and uncomfortable at first, Caïn was able to overcome those feelings to focus on other, more pleasant things (such as Park’s breath in his neck, Park’s other hand which was holding him firmly by the waist, or Park’s arched back that Caïn was discovering under his fingers and Caïn had never realized that Park’s muscles were defined but he never really had the chance to see him naked before, and anyway it was very nice.)

“I guess you don’t have condoms either,” Park said suddenly.

Caïn opened an eye, unsure of what he had just heard, still focused on what was going on between his legs, and not really thinking about material things such as condoms or the way Park was going to put his dick inside him – Caïn wasn’t afraid of it, he was just too busy being fingered to care about something else at the same time.

“Wh-at?” he only managed to ask.

“Don’t tell me you don’t know what condoms are?!”

Park was looking at him with a shocked look which would have made Caïn laugh in literally any other circumstances.

“I know what condoms are!” he grumbled, “why do you have to ask that now?”

“Because it’s the next step? You know before I put that thing of mine inside you,” he pointed a finger at his crotch which Caïn followed with his gaze and regretted immediately when he started blushing, Park didn’t see it, or didn’t mind, he kept talking, “we need protection. Not that I’m not clean but it’s safer and also I don’t want to give you bad habits. I’m training you at this after all.”

“Training me?” Caïn pointed out.

“Am I not your first time?”

Caïn blinked, then blushed again and looked away.

“Yes. Yes, you are,” he whispered, “but I thought you were having sex with me because you wanted to, not because you felt the need to teach me or something.”

Caïn bit his lip again, forgetting that it still hurt, he grimaced.

“If I wanted to have sex just to _have sex_ , I would have asked anyone else,” he said.

“You would have asked anyone else to fuck you?”

Park’s voice was blank of emotion and Caïn didn’t know if it was a tricky question, if his answer could offend Park and make him leave right after. If it were to happen, Caïn didn’t know if he would be more ashamed, frustrated, or angry.

“Yes,” he answered.

“But you asked me.”

“Yes,” Caïn said.

“Because you want to have sex with me.”

“ _Yes_ ,” Caïn said again, he was starting to feel irritated and he still avoided Park’s look, “what with all those questions? Are you done with your fingers? It’s getting uncomfortable.”

Park’s digits immediately left Caïn and it felt even weirder, he squirmed again, crossing his legs, ill at ease and unsure of what he was supposed to do next. Park was looking at him and his hand was resting on his hip, caressing him from the tip of this finger, gently. Caïn didn’t want their gaze to meet and Park must have noticed, because his other hand brushed his cheek.

“Caïn”, Park called, “look at me.”

Caïn did not even try to pretend that he could resist him. His gaze went back to Park right away, and their eyes locked. Caïn felt the heat on his face grow stronger at the way Park’s eyes were almost glowing, his gaze warm and intense, focused on him. Caïn quivered.

“I do want to have sex with you,” Park said, and Caïn didn’t know why he felt so relieved suddenly.

“Oh,” he said, “glad to hear it at last.”

Park smiled, then kissed him. Caïn opened his mouth to give him better access, and Park kissed him harder, ignoring Caïn’s sharp teeth and, Caïn was sure of it, enjoying the moans he couldn’t restrain. Caïn felt the last snippets of his discomfort being blown away by Park’s firm lips pressed against his and the way their tongues were playing together. Caïn lost himself in the kiss and before he could fully realize it, he was arching his back, eager to feel Park’s body against his, to feel him, entirely, against his skin, against him, _inside_ him – and the mere thought of it made Caïn moan even louder.

This time, Park didn’t ask him to calm down. The kiss eventually ended only for Park to kiss Caïn’s jaw, then ears, and neck, and soon he was sucking on his pale skin, but lightly, as if he didn’t want to leave marks, but still wanted Caïn to feel his teeth.

“We don’t need it,” Caïn said suddenly.

Park looked up at him with a questioning gaze.

“The condom. You don’t need to wear one. I trust you.”

Park frowned. Caïn wondered if he was going to disagree with him, and treat him like a kid again, saying that he was irresponsible and immature – which Caïn knew, because he was well aware of the risks, but he did trust Park and he didn’t want him to do some weird magical thing to conjure a condom or whatever. Caïn _was_ needy, and right now he just wanted Park to fuck him, condom or not, he was running out of patience.

After an instant, Park smiled again.

“You shouldn’t trust me so easily,” he said with a grin.

“I know,” Caïn answered, then he grabbed Park’s shoulders and forced him into another passionate kiss that he made sure to lead until the end (and Park let him.)

Caïn felt both of Park’s hands slide down his torso to his waist, then his hips, then his legs and, instinctively, Caïn spread them wider when Park’s finger posed on his inner thighs. Caïn tried to focus on the way Park’s lips were moving against his, then against his skin when Park left myriads of kisses along the line of his shoulder. Then Park kissed him gently on the cheek and said:

“I want you to focus on my eyes, okay? Just focus on my eyes and relax.”

Caïn nodded, and his gaze did not let go of Park’s eyes, just as he had asked. He guessed more than he saw that Park positioned himself above him and Caïn tried hard not to squeeze his eyes shut. He kept them open, and his gaze stayed locked with Park’s, yellow irises that seemed to be shining with delight over him, Caïn almost lost himself in them. Nothing else mattered but Park’s gaze on him. Nothing else mattered but Park’s eyes focused on him. Nothing else mattered but _Park_ -

And then Park was inside him, and Caïn let out a cry.

“F-fuck-” Caïn whined, “that’s bigger than your fingers.”

Above him, Park laughed, which made his body shudder, and Caïn felt it immediately between his legs. He squirmed and cursed again.

“Watch your pretty mouth,” Park warned, but his voice was soft like honey and Caïn thought that this comparison suited him perfectly.

Taking a deep breath, Caïn tried to adjust to the new sensations. His eyes were still focused on Park who had not let his gaze down nor shown any sign of discomfort or anything else related to the fact that he had just put his penis inside Caïn for the first time and Caïn could have admired that if he wasn’t busy trying to get used to said penis. Caïn swore to himself that he was going to change that expression on Park’s face before the end of their intercourse. He had told Park that he was going to make him moan, and Caïn wasn’t one to go back on his words.

“I’m going to move,” Park said after a few seconds, “you okay?”

Caïn nodded.

“Yeah, just… be gentle? Please…”

Park’s smile seemed to soften a little and he gently kissed Caïn on the corner of his mouth. Caïn was always surprised by how Park could juggle so easily between different emotions. He seemed so careless one second, and then the next one he was suddenly attentive and caring, and Caïn could have just melted under him.

“Of course,” Park said, “anything you want, sweetheart.”

Caïn shivered. Oh, _god_. He didn’t know he could love pet names that much, yet here he was, blushing just because of one word (and the way Park said it had probably something to do with it, because Caïn had heard his mother call him sweetheart before, and it did not have the same effect, _at all_.)

The first thrust made Caïn groan in discomfort, but he tried not to show it too much because he didn’t want Park to stop. He made sure to keep his eyes open and kept them focused on Park’s face, who was looking back at him with his eternal smile. Park started slowly, as he had promised and soon he was kissing Caïn again, gently sucking on his lips, his ear, the skin of his neck, and he started whispering sweet nothings to Caïn who listened to everything very carefully. Every word that Park pronounced was like a promise, warm like fire and sweet like honey, and it made Caïn’s consciousness melt a little bit more every second that passed by. Eventually, he was able to relax enough for the sensations to become less uncomfortable, even pleasant, and then he started moaning.

The first moan surprised him, and he tightened his grip on Park’s shoulders, suddenly very aware of his own body and what was going on in it. Caïn felt a new warmness inside him, flooding through his lower body, up to his chest and down to his crotch, as if the discomfort he had felt at first had directly transformed into pleasure.

This wasn’t the first time that Caïn was feeling sexual pleasure, but there was something different in the way he was feeling it now: it wasn’t him and his hand lazily jerking himself off to release some tension that had built up because of a morning dream; it was because of someone else, it was because of _Park_ , and it was _inside_ him. Caïn let out another moan before he could even think about it. Park’s smile widened.

“Does it feel good?” he asked, his voice deep and slow against Caïn’s ear, and Caïn only managed to hum in approval, because the way Park talked and the way he moved against him, the two combined, almost made him feel dizzy.

But Caïn didn’t want to let Park believe that he was just an overwhelmed teenager enjoying his first time like some innocent maid. He wasn’t a kid anymore, he was a demon, and as much as Caïn still hated the fact that it was happening to him, he couldn’t help but take pride in his nature. Supernatural beings were known to be strong, and Caïn intended to show it to Park, that he wasn’t as weak and helpless as he thought.

“Park,” Caïn called, barely opening his lips, his breath hot and his fingers still clenched to Park’s shoulders.

“Hm?”

Caïn searched for Park’s gaze, staring at his face until their eyes locked. Park kept smiling and Caïn wished he would stop now, because Caïn didn’t want Park to smile anymore, he wanted him to moan, to feel as good as he did, and to show it to him. Caïn wanted to make Park feels things, and he wanted it right now.

Caïn spread his legs wider, arched his back and his hips met Park’s halfway the next thrust, taking Park deeper inside him. He watched Park’s expression twitch, and Caïn couldn’t help but smile, too, when he saw that Park restrained a moan.

“Does it feel good?” Caïn asked, taking the most innocent tone, but his grin was hardly unnoticeable.

Caïn was particularly satisfied to see Park’s expression change at last: he frowned. Caïn immediately felt something drop in his stomach, because Park had not lost his smile, and now he looked threatening, and _oh_ , Caïn didn’t think he would enjoy it that much.

“You want to play with me?” Park asked, and Caïn only nodded, too happy to have got his attention all over him, _really_ , all over him, at last. “Alright, baby boy. If you want it so badly, I’m gonna give it to you.”

Caïn only got a second to brace himself and then Park was kissing him roughly, pressing his tongue in his mouth and biting on his lips without a care for the little wound Caïn had from earlier. Caïn gasped for air, but Park didn’t care, he kept on kissing him, and at the same time, his hands, which were gently holding Caïn by the waist until then, slid down to Caïn’s legs; he took his right thigh and pushed it up, before thrusting hard into him. Caïn’s loud moan was immediately swallowed into their kiss.

From there, Caïn let Park lead everything, lazily giving in every sensation he felt, enjoying each one to the most, and occasionally sinking his nails into the skin of Park’s back when he was thrusting harder into him. Caïn did not notice how deep he was scratching until he heard Park groan in his ear.

“Your nails,” he said, his voice too husky to make it sound like a complaint, but warm enough to make Caïn shiver in anticipation, “calm down kiddo.”

Cain realized that he was panting, and he immediately let go of Park’s back to fall back on the mattress. He looked up to look at Park and saw that his eyes were still shining but not with amusement anymore. Caïn wondered if he was angry, if he had hurt him, until he recognized the look.

Park’s eyes were shining with _lust_.

And _desire_.

That’s when Caïn realized that when Park was telling him to calm down, he was, in fact, warning him. The grin that took place on Caïn’s face at this moment was almost genuine. He didn’t know why nor how, but it was as if could actually _feel_ Park’s desire for him, almost like a tangible thing. And it wasn’t just because they were fucking - which was obviously due to their mutual arousal and yearning – no, there was something else, something less physical and almost… supernatural?

Caïn gasped as Park suddenly hit a spot inside him that literally made him see stars. The sensation immediately made him forget about what he had just noticed, and he closed his eyes shut and let out a proper cry of pleasure as Park reached his prostate again. Caïn found himself muzzled by Park’s hand, and then his lips when he kissed him in an almost gentle way that contrasted so much with how he was currently pounding into him.

Caïn began to lose track of where he was and what was going on as the pleasure he felt overcame him completely, from his crotch to his chest and the tip of his fingers. He had never felt something like that before, and he already knew that he would need it more than just once. He barely opened his eyes to take a look at Park who had straightened up to have a better position between his legs he was still holding firmly. His short dark hair was stick to his forehead with sweat and he was panting as well, and Caïn was exulted to see that he had lost his smile at last.

Park was still incredibly handsome nonetheless and Caïn felt a tender satisfaction at the idea that he was the only thing that Park was focused on now. Just him, and no one else. Caïn could live like this.

“Park,” Caïn called him between two moans, “Park-”

Park leaned back over him, but Caïn noticed that he carefully avoided putting his entire weight on him. Park kissed his smile and whispered against his lips:

“Hm? What is it, baby?”

Caïn’s smile grew wider. Oh, he loved that _so much_. He could _definitely_ live like this.

“Oh, it’s just…” Caïn bit his lip. He felt like saying so many things to Park, so many thoughts he had had since they had started this, so many words he wanted to share with him about how good he felt, and how much he loved everything Park was doing to him.

But Caïn couldn’t say _all_ those things, so he settled on only one that he was sure would have its effect on Park.

“You just look so good when you’re inside me, I think I’m gonna come.”

Park’s face at this exact moment was everything Caïn ever wanted to see.

Then Park hit his prostate hard and Caïn shut his eyes to let out a loud moan. The tension that had built up inside him was reaching its peak and he was definitely going to come soon.

“Now, would you look at you,” Park’s husky voice was right into his ear and Caïn moaned again just by the sound of it, “all worked up already. Were you trying to make me come before you? Hm? With all your tricks? Where did you learn that from, baby boy?”

Caïn knew he wasn’t expected to answer anything because Park had started jerking him off with his free hand, and Caïn couldn’t think straight, let alone talk when the only sounds he could make were gasps, moans, and cries of pleasure. Not that he would complain, though, he loved it. He opened his eyes slightly and smiled back at Park.

“I learnt- ha-a, I learnt by myself, just to please you-” he managed to say before letting out another moan.

The truth was: Caïn didn’t know when he had learnt all those things, but he felt pretty confident about it, and he enjoyed it, a lot. It almost felt instinctive, as if it was something he was _meant_ to do.

Park kissed his temple before slamming into him once more and Caïn gasped and grabbed his hair to hold on to something.

“Oh yeah? Good boy,” Park purred, “you’ve been really good for me Caïn, haven’t you?”

“Yes!” Caïn cried out, “Just for you, P-Park, I’m… good, ah- _please_!”

“It’s okay baby boy, you can come,” Park finally said, and Caïn didn’t even know he needed to hear his permission to feel it.

“ _Come for me_ ,” Park whispered into his ear.

And so Caïn did.

He climaxed in a mess of feelings, sensations, and semen, and the last moan he let out – a loud, long and shaky moan – was enough to summarize all of it. He held on to Park as the orgasm was flooding through him and he squeezed his eyes shut to enjoy every single wave. Caïn didn’t think he had ever felt something as powerful and pleasurable as this in his life, and it was purely amazing.

Afterward, Caïn barely felt Park moving but he still managed to grab him and stop him from completely moving away from him.

“What are you doing?” Caïn asked, his voice hoarse and his mind still clouded with the last remaining of his orgasm. “Why am I the only one who came?”

Park sighed.

“I’m not wearing a condom and I don’t want you to feel dirty.”

Caïn blinked. After everything they had done, Park still cared so much about his well-being that it made Caïn laugh. Then he pouted, because, _really Park_?

“But I want you to come inside me.”

Caïn saw how Park’s adam’s apple moved when he gulped and he couldn’t help but be proud of the effect he had on him, just with a few words. And since he was feeling bold, and still groggy from his earlier orgasm, he even pushed it further as to test if he could make Park give in to him in one go. That would be a premiere, and that would be a great premiere.

Caïn straightened up a little and, in the exact same way Park had done so many times, he whispered into his ear, his voice like a purring:

“I want you to fill me up _entirely_ , Park.”

Caïn felt more than he saw Park shudder, so he just added one little thing he knew Park would never resist. He begged:

“ _Please_.”

“ _Fuck_ ,” was all Park managed to answer before he slammed his cock deep inside Caïn for a few last desperate yet vigorous thrust that almost made Caïn feel over the edge again.

( _God_ , would he _ever_ be satisfied?)

He did, though, when Park climaxed inside him, filling him up exactly the way he asked him to, and Caïn thought that Park’s face during his orgasm was the most beautiful thing he had ever seen, so he kissed him. Park moaned against his lips and Caïn tasted it like the most delicious sweets. He loved that – hearing Park moan – he loved it so much he wanted to hear it again.

Unfortunately, once he had completely climaxed, Park lazily fell on him, and Caïn only grimaced when he eventually felt how sticky they were.

“You’re heavy,” Caïn complained.

“You asked for it,” Park answered without moving an inch.

He did eventually and Caïn grimaced because the discomfort in his lower body was now persistent. Park laid down next to him and looked at him with a playful gaze Caïn knew by heart by now. Caïn squirmed and turned on his side to face him, which made him groan in discomfort again.

“You hurt?” Park asked, “Where?”

“Take a guess,” Caïn said, sarcastic.

Park only smiled for an answer. Then he raised his hand and placed it on Caïn’s lower back. Caïn was about to ask him what he was doing when he felt a soft warmness coming from Park’s hand and flooding directly through his body. It eased the pain immediately and Caïn let out a contented breath.

“Better?” Park asked, his eyes glowing with magic.

“Yeah,” whispered Caïn.

He felt suddenly so warm and nice, now that the pain had disappeared, his eyes were closed before he could act on it. Instinctively, he drew closer to Park, and soon he was wrapping an arm around him, and burying his head in the crook of his neck. Park didn’t move, which meant he didn’t reject him, even if he didn’t do anything to hug him back either. Caïn didn’t ask for more, yet. Just feeling Park against him was enough for now.

Caïn knew he was dozing off, even if he didn’t want to, and he wondered if Park had not put a spell on him for it to happen so quickly. Caïn wanted to protest. He wanted to keep talking to him, and kissing him, and hugging, and everything else he felt like he wanted to do with Park since that first kiss, two months prior. Caïn smiled thinking about that kiss again, and to how it had eventually lead him there, naked in Park’s embrace after his first-ever sex experience. To be honest, it was exactly what he had expected from today, so he wasn’t disappointed in the slightest.

“Park…” he managed to call before completely falling asleep.

“Hm?” Park answered, he was brushing Caïn’s back now, and Caïn knew it was just another trick to make him fall asleep faster, no matter how nice it felt.

“You won’t be there tomorrow morning, will you?”

Silence. Park kept caressing his back, slowly.

“No, I won’t,” he said eventually.

“Okay.”

That’s all Caïn needed to know.

“Thank you,” he said.

He heard Park chuckle and it vibrated in his body. Caïn loved to hear Park laugh.

“You’re welcome kiddo,” Park answered, “happy birthday.”

Then he kissed Caïn on the forehead, and Caïn fell asleep.

When Caïn woke up the next morning, he was, indeed, alone.

He was in his pyjamas and under the sheets of his bed which had been magically cleaned. He felt warm, nice, and clean, and also happy. Caïn thought that he had not felt this happy in months.

Getting up and leaving his bed to get ready for his day, he went to the bathroom. There, he met his reflection in the glass and blinked.

For the first time, Caïn didn’t feel disgusted when he looked at himself. His red eyes didn’t scare him, instead, they looked almost… appealing. _Captivating_.

Caïn bit his lower lip and grimaced. He realized that his fangs were still out and he opened his mouth to better check on it. His four canines were out, white as milk, almost shining, and sharp like knives.

Caïn thought about what he could do with them – and to who he could do it – and he smiled.

Maybe being a demon wasn’t _that_ bad. Maybe he would grow into liking it.

Caïn left the bathroom and turned the light off. He was going to be late for his first class.

Park was not even surprised to learn that Caïn was a lust demon. At first, he wondered if he had something to do with it until he thought about the way Caïn had literally begged him to fuck him on his sixteenth birthday.

Yup.

 _Definitely_ a lust demon.

Caïn could have found out way earlier, Park thought, if he weren’t so stubborn and obsessed with the fact that he didn’t want to become a demon – though he had seemed to enjoy it a lot at the time.

Park smiled and reassured Caïn’s dad the best that he could.

“Don’t worry, he is great at it,” he said, confident.

Caïn’s dad seemed a bit surprised by such a statement and it took a few seconds for Park to understand why.

“I mean,” he chuckled, “he is good at everything he does, isn’t he? He’s going to be a great lust demon as well.”

Caïn’s dad didn’t seem really convinced. Park winked at him with a smile and that was the best he could do to reassure him – because he was pretty sure that telling him that he had already tested the powers of his son was not the best of moves.

Park patted the man’s shoulder.

“I’ll keep an eye on him anyway, don’t worry about it.”

Caïn’s father nodded.

“Thank you very much Park. I don’t know how I can repay you for everything you’ve done for us… for Caïn.”

“Oh, it’s okay, the kid knows how to thank me enough.”

Caïn’s father frowned, but Park said bye and disappeared before he could ask him what he meant.

**Author's Note:**

> Hope you love Park and Caïn as much as I do (because I love them very very much); don't hesitate to leave a comment to tell me anything!! Even not related things, if you feel like it??


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